<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<label>
    <input id="test-ipt" value="111"/>
</label>
<br/>
<button id="get-btn" type="button">简单获取属性</button>
<br/>
<button id="set-btn" type="button">简单设置属性</button>
<br/>

<script type="text/javascript">

    window.onload = () => {
        let testIpt = document.querySelector("#test-ipt");
        document.querySelector("#get-btn").onclick = () => {
            console.log(testIpt.value);
            console.log(testIpt["value"]);
            console.log(testIpt["aaa"]);
        };

        document.querySelector("#set-btn").onclick = () => {
            testIpt.value = "222";
            testIpt["value"] = "333";
        };
    };
</script>
</body>
</html>